The present invention relates to a housing, particularly a filter housing, especially an air filter housing, comprising first and second housing sections which can be releasably connected by a relative rotational movement between the sections.
Hollow cylindrical air filter housings with bayonet locks are known in the art. Bayonet locks of this type typically have latching surfaces on one housing section and latching projections on the housing section to be connected thereto. To connect these two housing sections, the latching projections and the latching surfaces are arranged in pairs. Depending on the size and the diameter of the housing, it has been found that two to eight corresponding latching pairs are suitable. Depending on the shape of the housing, the latching pairs are arranged radially in series or opposite one another. In the interior of the housing, hollow cylindrical filter elements with radial flow or cylindrical filter elements with axial flow are normally used. When servicing is necessary, these elements must be replaced. The housings must therefore be separable in such a way that this replacement can be performed without any difficulty. Servicing is simple with the above-described bayonet lock and requires no tool.
Published international application no WO 99/14483 A1 discloses various embodiments of a bayonet lock for assembling hollow cylindrical air filter housing sections. In this case, a hollow cylindrical cover member is connected to a hollow cylindrical lower housing section via a bayonet lock. To this end, the cover member is provided with corresponding latching elements in the vicinity of the cylindrical connection opening along the interior lateral circumferential surface. The lower housing section, on the other hand, has the respective latching elements in the vicinity of the cylindrical connection opening along the exterior lateral circumferential surface. In one embodiment, the latching surfaces are L-shaped, such that one of the legs is arranged parallel to the rotational locking movement and the other leg is arranged perpendicular thereto. The corresponding latching projection on the other housing section is U-shaped. In another embodiment, the latching plane is P-shaped and the associated latching projection banana-shaped. The portion of the latching plane perpendicular to the rotational locking or unlocking movement acts as a limit stop in both the L-shaped and the P-shaped configurations. In both embodiments, the same latching pairs are always used. Each latching pair performs the function of adjusting the torque required for locking and unlocking, adjusting the securing force and adjusting the radial and axial play in the locked state.
Apart from the well-known advantages, such as low cost, simple handling and high integration, the state of the art described above also has some disadvantages. Particularly adjustment has to be rated as problematic in the prior art solution. In the above-described bayonet solutions, the parameters to be adjusted are combined in the respective latching pairs, so that modifying one function also modifies one or more other functions. The functions, in this case, are torque during locking, torque during unlocking, clamping force in the axial direction, clamping force in the radial direction, play in the axial direction and play in the radial direction. The drawback that modifying one function also modifies one or more other functions makes adjustment substantially more difficult, because not every desirable combination is possible and a compromise is always necessary.